Changing the currently open tab in graph editor with Python
Old question I know. I found this: https://wiki.blender.org/index.php/Dev:Doc/Projects/UI/Tab_Guidelines

you have a panel right?
People seem to need a property called bl_category be set to the tab page name they want to place it on.
In regard to this question it may be:

class panelName(bpy.types.Panel):
      bl_category = "Modifiers"

Also, changing the focus is a completely different task